76421561 has 4 divisors (see below), whose sum is σ = 77097972. Its totient is φ = 75745152.

The previous prime is 76421557. The next prime is 76421563. The reversal of 76421561 is 16512467.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 383161 + 76038400 = 619^2 + 8720^2 .

It is a cyclic number.

It is not a de Polignac number, because 76421561 - 2² = 76421557 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (76421563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 338036 + ... + 338261.

It is an arithmetic number, because the mean of its divisors is an integer number (19274493).

Almost surely, 2^76421561 is an apocalyptic number.

It is an amenable number.

76421561 is a deficient number, since it is larger than the sum of its proper divisors (676411).

76421561 is a wasteful number, since it uses less digits than its factorization.

76421561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 676410.

The product of its digits is 10080, while the sum is 32.

The square root of 76421561 is about 8741.9426330765. The cubic root of 76421561 is about 424.3640981479.

The spelling of 76421561 in words is "seventy-six million, four hundred twenty-one thousand, five hundred sixty-one".